Arc-lamp electrode



Feb. 13. 1923. 1,444,961.

\ 'H. B. EYNON.

ARC LAMPELECTRODE.

nu-:0 JUNE 11, 1919.

I'LB. EYNUN ATTORNEY Patented Feb. 13, 1923. I

at it. la. 9

HOWARD B. EYNON, OF LAKEWOOD, OHIO, A SSIGNOR TO NATIONAL CARBONCOMPANY, INC., A CORPORATION OF NEW YORK.

ARC-LAMP ELECTRODE.

' Application filed June '11,

T all whom it may concern:

Be it known that I,HO\VARD B. EYNON, a citizen of the United States,residing at Lakewood, in the county of Cuyahoga and State of Ohio, haveinvented a certain new and useful Improvement in Arc-Lamp Elec trodes,of which the following is a full, clear,

and exact description.

This invention relates to an improvement I negative electrodesespecially adapted for use in projection apparatus.

One of the most important requirements which must be fulfilled for thistype of service is are steadiness and my. invention relates to,'andespecially discusses an electrode structure which satisfies thisparticular requirement.

I have found that the arc has a very strong tendency to spring from thehottest part of a negative electrode and to remain there. I have foundthis to be especially true in the case of pure .carbon electrodes orwith electrodes in which no flaming ingredient is present in closeproximity to the portion .of.

the electrode from which the are springs. Although the same is true ofelectrodes containing small amounts of flaming material to a limitedextent, the presence of flaming material is undesirable because itreduces the temperature of the 'arc stream and the intrinsic brilliancy.i 1 A preferred embodiment of the invention is illustrated in theaccompanying drawing, which shows a vertical section through theimproved electrode. a Referring to they drawing, reference character 1designates an. outer shell preferably of pure carbon. The shell'afterbaking is tively. porous carbon. I v trodcis used in combination with asuitable in arc lamp electrodes, and particularly tov 1919. Serial No.303,301.

provided with a core 2 consisting of carbon 40 flour. mixed with acarbonaceous binder, such 5 as a mixture oftar and benzol. After coringthe article is dried or baked to set'the binder. This results in apractically pure carbon article having a shell of dense ca'rbon and acentral core of less dense and rela- When such an elecpositive,-the arcwill tend to spring from the-central core during burning" because whenthe are springs therefrom the core does not conduct heat to the shellreadily. The spot from which the arc springs therefore tends to have ahighertemperature for the reason given. On account of its centrallocation there is also a greater tendency for the arcyto spring from thecore'than from the surrounding shell. a

Although I have set forth what, I be- :lieve is a reasonable explanationof the steadinessof the electrodes, it must be understood that myinvention is not necessarily limitedtheretop 'Having described -myinvention, what I" claim is:.-. -A negative. electrode havinga bodyportion consisting entirely of carbon, said body portion comprising arelatively dense and substantially pure carbon shell, and a core forsaid shell consisting of. a-relatively less densefiller ofcarbonaceousmaterial having a carbonaceous binder incorporatedtherewith, such filler being a good electrical conductor and a poorconductor'of heat.

In testimony whereof, I hereunto affix my signature.

HowA-Ri B. EYNON.

